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At 12 months, patients with congestive heart failure and/or left atrial enlargement had an atrial fibrillation detection rate of 23.4% vs 5.0% for patients with neither attribute.
Lee Schwamm, MD
Using an insertable cardiac monitor (ICM), findings from a prespecified analysis of the STROKE-AF trial (NCT02700945) identified several risk factors associated with poststroke atrial fibrillation, the most significant being congestive heart failure (CHF) and left atrial fibrillation (LAE). Investigators noted that these patients may benefit most from the use of ICMs as part of a secondary stroke prevention strategy.1
The analysis included 242 participants randomly assigned to the ICM from the trial, 27 (11.6%) of which had AF detected at 12-month follow-up. Among the numerous factors found attributable to poststroke AF, a multivariable analysis showed that only CHF (HR, 5.06; 95% Ci, 1.45-17.64; P = .05) and LAE (HR, 3.32; 95% CI, 1.34-8.19; P = .009) were associated with an increased likelihood of detecting AF during monitoring, with a trend toward significance for QRS duration (HR, 1.02; 95% CI, 1.00-1.04; P = .06).
Lead investigator Lee Schwamm, MD, vascular neurologist, Massachusetts General Hospital, and colleagues concluded that "Although preliminary in nature, if the findings from our study are replicated in other cohorts, then the associations of CHF and LAE with AF may be useful when considering an ICM in routine poststroke clinical care." Notably, the study was not powered to detect clinical predictors of AF, and therefore, other clinical characteristics may have not reached statistical significance.
Patients were 60 years or older or aged 50 to 59 years with at least 1 stroke risk factor. In the original trial, participants were randomly assigned 1:1 to AF monitoring using the Reveal LINQ monitoring system within 10 days of index stroke vs site-specific usual care. The ICM detected AF episodes of 2 minutes or longer, and first episodes of AF were adjudicated by a clinical events committee to confirm its diagnosis.
The newly announced prospective, randomized, placebo- and sham-controlled study, will include 150 patients, ages 18 to 55 years, with documented patent foramen ovale and a history of more than 1 migraine headache day per week.
To address high rates (40.8%) of missing left atrial volume index (LAVI) values, a post hoc composite variable for LAE as created and used for the primary analysis. Participants were classified as having LAE if they demonstrated LAVI greater than 28 mL/m2, LA diameter greater than 41 mm for males and 39 mm for females, and no measurements for LA volume or diameter, but LAE was documented in the echocardiography report.
Among the 27 individuals with detected AF, 26 (96.3%) first episodes were asymptomatic. None of the 7 participants who crossed over to the control group had AF detected. All told, variables identified as univariate predictors of AF, based on a nominal P value of <.10, included LAVI per 10-mL increments (HR, 2.30; 95% CI, 1.58-3.34; P <.001), LAE (HR, 3.63; 95% CI, 1.55-8.47; P = .003), chronic obstructive pulmonary disease (HR, 2.49; 95% CI, 0.86-7.20; P = .09), CHF (with preserved or reduced ejection fraction: HR, 6.64; 95% CI, 2.29-19.24; P < .001), kidney dysfunction (HR, 3.58; 95% CI, 1.35-9.46; P = .01), age (per 1-year increments: HR, 1.05; 95% CI, 1.01-1.09; P = .02), CHA2DS2-VASc score (per point: HR, 1.54; 95% CI, 1.15-2.06; P = .004), QRS duration (HR, 1.02; 95% CI, 1.00-1.04; P = .04), and LA diameter (per millimeter: HR, 1.05; 95% CI, 0.99-1.11; P = .08).
As previously noted, only CHF and LAE were associated with an increased likelihood of detecting AF after the multivariable analysis; however, there were no statistically significant interaction between CHF and LAE. Notably, the rate of AF detection at 12 months among those with either CHF and/or LAE (40 of 142 patients) was significantly higher than patients with neither attribute (23.4% vs 5.0%; HR, 5.1; 95% CI, 2.0-12.8; P <.001).
